Speaker
Description
Extreme blazars (EHBLs) are mostly characterized by a synchrotron peak located at energies > 1 keV, and by the hardness of the spectrum in the high-energy (HE, E > 100 MeV) range. So far, only a handful of these objects have been detected at very-high energies (VHE, E > 100 GeV) by Imaging Atmospheric Cherenkov Telescopes. Moreover, multi-wavelength observations of some of these blazars (like 1ES 0229+200) have provided evidence of a VHE gamma-ray emission extending to several TeV, which is difficult to explain naturally with standard, one-zone synchrotron self-Compton models for BL Lac objects. Furthermore, their GeV-TeV spectra also shed new light on the blazar sequence.
Since 2010, nine EHBLs have been observed in different observing multi-wavelength campaigns of the MAGIC telescopes, aiming to increase the number of known EHBL TeV-emitters. Three sources have been clearly detected at TeV energies by the MAGIC telescopes. In this contribution, I will present the results of the multi-wavelength campaigns. In particular, the GeV-TeV behaviour of these sources will be presented and compared to the known EHBL prototype (1ES 0229+200).
